Savant Syndrome





Savant Syndrome is a rare, but spectacular, condition in which persons with various developmental disabilities, including Autistic Disorder, have astonishing islands of ability or brilliance that stand in stark, markedly incongruous contrast to the over-all handicap. In some, savant skills are remarkable simply in contrast to the handicap (talented savants). In others, with a much rarer form of the condition, the ability or brilliance is not only spectacular in contrast to the handicap, but would be spectacular even if viewed in a normal person (prodigious savant). There are fewer than 100 reported cases of prodigious savants in the world literature. The condition was first named Idiot Savant in 1887 by Dr. J. Langdon Down (better known for having named Down\'s Syndrome). He chose that term because the word "idiot" at that time was an accepted classification level of mental retardation (IQ below 25) and the word "savant" meant knowledgeable person derived from the french word savoir, meaning "to know". The term idiot savant has been largely discarded now, appropriately, because of its colloquial, pejorative connotation and has been replaced by Savant Syndrome. Actually Idiot Savant was a misnomer since almost all of the reported cases have occurred in persons with IQs of 40 or above. The condition can be congenital or acquired in an otherwise normal individual following CNS injury or disease. It occurs in males more frequently than in females in an approximate 6:1 ratio.
Savant skills occur within a narrow but constant range of human mental functions, generally in six areas: calendar calculating; lightening calculating & mathematical ability; art (drawing or sculpting); music (usually piano with perfect pitch); mechanical abilities; and spatial skills. In some instances unusual language abilities have been reported but those are rare. Other skills much less frequently reported include map memorizing, visual measurement, extrasensory perception, unusual sensory discrimination such as enhanced sense of touch & smell, and perfect appreciation passing time without knowledge of a clock face. The most common savant skill is musical ability. A regularly re-occurring triad of musical genius, blindness and autism is particularly striking in the world literature on this topic. Premature birth history is commonly reported in persons with Savant Syndrome.
In some cases of Savant Syndrome a single special skill exists; in others there are several skills co-existing simultaneously. The skills tend to be right hemisphere in type--nonsymbolic, artistic, concrete, directly perceived--in contrast to left hemisphere type that tend to be more sequential, logical, and symbolic including language specialization.
Whatever the special skills, they are always linked with phenomenal memory. That memory, however, is a special type--very narrow but exceedingly deep--within its narrow confines. Such memory is a type of "unconscious reckoning"--habit or procedural memory--which relies on more primitive circuitry (cortico-striatal) than higher level (cortico-limbic) cognitive or associative memory used more commonly and regularly in normal persons.
Approximately 10% of persons with Autistic Disorder have some savant abilities; that percentage is much greater than in other developmental disabilities where in an institutionalized population that figure may be as low as 1:2000. Since other developmental disabilities are much more common than autism, however, the actual percent of persons with Savant Syndrome turns out to be approximately half Autistic Disorder and half other Developmental Disabilities.
Theories to explain Savant Syndrome include eidetic imagery, inherited skills, concrete thinking and inability to think abstractly, compensation & reinforcement, and left brain injury with right brain compensation. Newer findings on cerebral lateralization, and some imaging and other studies that do show left hemisphere damage in savants, suggest that the most plausible explanation for Savant Syndrome to be left brain damage from pre-natal, peri-natal or post-natal CNS damage with migratory, right brain compensation, coupled with corresponding damage to higher level, cognitive (cortico-limbic) memory circuitry with compensatory take over of lower level, habit (cortical-striatal) memory. This accounts for the linking of predominately right brain skills with habit memory so characteristic of Savant Syndrome (Treffert, 1989). In talented savants, concreteness and impaired ability to think abstractly are locked in a very narrow band but, nevertheless, with constant practice and repetition can produce sufficient coding so that access to some non-cognitive structure or unconscious algorithms can be automatically attained. In prodigious savants, some genetic factors any be operative as well, since practice alone cannot account for the access to vast